The first zoo was formed in China in the 12th century B.C. But it was not called a zoo. Wen, the ancient Chinese king who started it, wanted to collect different types of animals from all over his empire. He kept them in what he called a 'garden of intelligence', near his palace.
Some of the largest zoos are in North America. There are big ones in the Bronx, New York City, and in Washington and San Diego.